Insole



FIG. 1 is a top plan view of an ornamental design for an insole; and,

FIG. 2 is a bottom plan view of the insole of FIG. 1.

The dash-dash-dash broken lines are included for the purpose of illustrating portions of the insole that form no part of the claimed design. 

CLAIM The ornamental design for an insole, as shown and described. 